Conveyance devices of this type are escalators and moving walks that have an endless arrangement of tread steps or tread plates, respectively. Adjacent to the long sides of the endless arrangement of tread steps or tread plates that extend in the direction of transportation are side, or upright, balustrades with handrails onto which persons who are present on the tread plates or tread steps can hold. The endless arrangement with the tread plates or tread steps and the handrails are, or can be, driven simultaneously, the handrails either slightly faster or synchronously.
There is frequently the need or desire to increase the transportation capacity of such conveyance devices.
The simplest solution that presents itself for this purpose is to increase the width of the tread steps or tread plates perpendicular to the transportation direction and thereby increase the mutual distance between the two side balustrades. This solution can, however, not usually be realized, because safety regulations restrict the mutual distance between the side balustrades to a maximum permissible value, with the purpose of ensuring that persons on the tread steps or tread plates can hold on to, or support themselves on, both side handrails or balustrades simultaneously.
Another arrangement to increase the transportation capacity of such a conveyance device is known from JP9-110350-A. There, in addition to a first endless arrangement of tread steps or tread plates, a second endless arrangement of tread steps or tread plates is provided which, with the exception of a boarding area and an exiting area, extends parallel and immediately adjacent to the first endless arrangement. The second endless arrangement of tread steps or tread plates has a faster-working motor or drive than the first endless arrangement. A first balustrade with handrail is located on the long side of the first endless arrangement, which faces away from the second endless arrangement. A second balustrade with handrail is located on the long side of the second endless arrangement, which faces away from the first endless arrangement. Between the two endless arrangements of steps or plates or pallets there is no balustrade and no other necessary handrail. It is foreseen that, in the boarding area, people in a hurry step onto the tread elements of the first endless arrangement, then change or jump onto the tread steps or tread plates of the second endless arrangement, and finally, in the exit area, change back to the tread steps or tread plates of the first endless arrangement. This greatly increases the danger of accidents, and cannot be expected of older persons. Also, persons who are not in a hurry remain on the tread plates or tread steps of the first endless arrangement, and are overtaken by those on the second endless arrangement.
This arrangement has several disadvantages. One is that it may be difficult to keep both endless arrangements so narrow that the maximum width prescribed by regulations is not exceeded. It may in any event be difficult for persons to support themselves with both hands at the sides, since the handrail of the second endless arrangement is presumably driven faster than the handrail of the first endless arrangement or escalator. Furthermore, here too, the total transportation capacity is limited by the access area and the exit area, both of which have only the width of the first endless arrangement. Finally, the accident hazard may be relatively high.
The task of the invention is therefore to propose an improved conveyance device of the type stated at the outset with which, in a simple manner and by simple means, while complying with the safety regulations, the transportation capacity can nonetheless be increased and material savings and cost savings achieved.